Process of treating anode residues.



UNITED STATES PATENT OFFICE.

ANSON e. BETTS, OF TROY, NEWYoRK.

PROQESS OF TREATING'ANODE RESIDUES.

SPECIFICATION forming part of Letters Patent No. 712,640, dated November4, 1902.

Application filed August 24, 1901. Serial No. 73,147. (No specimens.)

T0 aZZ whom it may concern.-

Be it known that I, ANSON G. BETTS, a citi senic in commercially-usefulform.

The object of my invention is to reduce the costs and losses attendingthe treatment of this material by known methods.

By my present method Iremove a considerable proportion of the lead,copper, antimony, and arsenic as chlorids from the anode residues byapplying thereto a chlorinating agent, such as potassium chlorate orferric salts in hydrochloric-acid solution. I have found out that thematerial being treated maybe suspended in hydrochloric-acid solution anda current of air blown through the mixture with a rather rapid solutionof the metals which form soluble chlorids. I prefer to use chlorin tochlorinate the metals, and especially prefer to have water present totake the chlorids formed into solution, which by the properties of themetals to form perchlorids soluble in water with chlorin and to reactwith the perchlorids to reform subchlorids insure that no chlorin islost. Enough chlorin should be introduced to convert most of the lead,copper, antimony, and arsenic present into lead chlorid, cuprouschlorid, antimony trichlorid, and arsenic trichlorid, respectively.

The solution produced when separated from the insoluble portion, mostlymetallic silver,

may be treated for the recovery of the metals in it in any known manner.

I prefer to distil off first the water, of which rather a small quantityneed be present, except in the rather unusual case when much copper ispresent, then the arsenic chlorid, and, finally, the antimony chlorid,while bismuth chlorid when present and copper and lead chlorids areallowed to remain undistilled. The lead dissolved as chlorid from theanode residues may be removed by precipitation with sulfuric acid, ifdesired. If the chlorin used be produced electrolytically, an amountofsodium hydroxid solution suflicient to convert the chlorids producedint-o oxids will be produced. This affords an easy method for recoveringthe arsenic and antimony in the form of oxids or salts-for instance,cupric arsenite and antimony trioxid. The latter can be directly smeltedto metal. The separation of the undistilled salts is easy to carry out.Treatment with water dissolves copper chlorid and lead chlorid ifpresent, While the his muth and uudistilled antimony remain undissolvedas oxychlorids. Copper may be removed from the solution by precipitationwith metallic iron, and the metals may be recovered from the oxychloridsby smelting. I prefer to dissolve the antimony from the oxychlorids bycaustic soda, leaving bismuth oxid undissolved.

The extent to which the chlorination may be carried in using my processmay be varied very much, the principal object being the removal of aconsiderable portion of the antimony, which interferes most in the subsequent refining of the unchloridized portion. Also the chlorination maybe carried so far as to convert silver into chlorid, which is removed toonly a small extent on account of its insolubilty.

The unchloridized portion of the anode residue is scorified and cupelledor treated by any of the known methods used in treating anode residuesfrom electrolytic copper refining.

What I claim as new, and desire to secure to arsenic present withchlorin gas, of removing them as chlorids in solution and of distillimgoff the water, antimonious and arsenious chlorids from sairlsolution.

In testimony whereof I have hereunto set my hand this 23d day of August,1901.

ANSON G. BETTS.

Witnesses:

S. D. NICHOLS, A. W. BURDIGK.

